The spinal column is a highly complex system of bones and connective tissues that provides support for the body and protects the delicate spinal cord and nerves. The spinal column includes a series of vertebrae stacked one on top of the other, each vertebral body including an inner or central portion of relatively weak cancellous bone and an outer portion of relatively strong cortical bone. Between each vertebral body is an intervertebral disc that cushions and dampens forces experienced by the spinal column. A vertebral canal containing the spinal cord and nerves is located behind the vertebral bodies.
There are many types of spinal column disorders including scoliosis (abnormal lateral curvature of the spine), kyphosis (abnormal forward curvature of the spine, usually in the thoracic spine), excess lordosis (abnormal backward curvature of the spine, usually in the lumbar spine), spondylolisthesis (forward displacement of one vertebra over another, usually in a lumbar or cervical spine) and other disorders caused by abnormalities, disease, or trauma, such as ruptured or slipped discs, degenerative disc disease, fractured vertebra, and the like. Patients suffering from such conditions usually experience extreme and debilitating pain, as well as diminished nerve function. Such disorders can also limit range of movement and threaten the critical elements of the nervous system housed within the spinal column.
One well known method of treating certain spinal disorders via surgical intervention is to immobilize regions of the spine, usually by fusing or joining adjacent vertebrae to one another. A variety of techniques have been disclosed in the art for achieving this immobilization. One such fusion technique involves removal of all or part of the intervertebral disc between two vertebrae, and implanting a bone fusion mass or bone graft in the resulting space and in contact with the vertebral end plates. As a result, natural bone growth fuses the two vertebrae together. In a similar procedure, known as a corpectomy procedure, one or more vertebral bodies and adjacent intervertebral discs are removed and a bone graft is then implanted into the space between the vertebrae to be fused. Corpectomy is commonly utilized to treat spinal disorders in the cervical (i.e., neck) region, although it can also be effectively used in the middle and lower spinal regions.
The above-mentioned fusion techniques may require the implantation of one or more devices to facilitate implantation of the bone graft and to stabilize the patient's spinal column until the target vertebrae have been fused by natural bone growth.
Accordingly, there is a need in the art for a device to facilitate the formation of a strong bone fusion joint between adjacent vertebrae. Additionally, there is a need for such a device to facilitate the distraction of the vertebrae to be fused and to provide structural stability to the joint prior to formation of the fused bone joint.